Russia is being ruled now by the nine-member Presidium, apparently held together by an "extraordinary discipline," Harold J. Berman, professor of Law and research associate of the Russian Research Center, said at a U.N. Council forum on "The Reorganization of the Soviet Power Structure" last night.

The chief and possibly fatal weakness in the organization of the Presidium is the lack of a pre-determined method of succession to power, he continued. While such a situation appears to invite dissension, Berman reminded his audience that the majority of Presidium members have held their posts for 15 years or more.

Undetermined Succession

Although Nikita Khruschchev now is party secretary, considered the position of most authority in the Soviet state structure, Berman feels that he has no more power inside the Presidium itself than any of the other members.

While no man as yet has asserted full control of the Presidium, no outside force, such as the army, is strong enough to dominate it, Berman said.

Zbignfew Brzezinski, instructor in Government, emphasized the fact that the role of the Army in Soviet politics is greatly exaggerated. The majority of generals who rise to political power from the army were politically appointed to the Army, and therefore lack the homogeneity of interests necessary for a power group, he said.